Heat the olive oil in a soup pot. Add the onion and celery and saute until golden. Add the potato and green beans along with enough bean cooking liquid, water or broth to cover. Bring to a boil, then simmer covered, over moderate heat until the vegetables are just tender, about 20-25 minutes. Add all remaining ingredients plus an additional 2 cups of liquid of choice. Simmer, covered, over low heat an additional 20-25 minutes. Season to taste with salt and pepper.